/Engine/Source/Runtime/Experimental/GeometryCollectionEngine/Public/GeometryCollection/GeometryCollectionEngineConversion.h
Appends a GeometryCollection to another GeometryCollection.
true if succeeded in appending a geometry collection
static bool AppendGeometryCollection ( const [FGeometryCollection](API\Runtime\Chaos\GeometryCollection\FGeometryCollection) * SourceGeometryCollection, int32 MaterialStartIndex, const FTransform & GeometryCollectionTransform, [FGeometryCollection](API\Runtime\Chaos\GeometryCollection\FGeometryCollection) * TargetGeometryCollection, bool bReindexMaterials )